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(No Model.)

TVA. EDISON.

' PHONOGRAM BLANK. No. 882,462. Patented May, 8.81888.

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UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF LLEWELLYN PARK, NEW JERSEY.

PHoNoeRAM-BLANK.

FJPECIPICATION forming part of Letters Patent No. 382,462, dated May 8, 1888.

v Application filed January 5, 1888. Serial No. 259,898. (No model.)

To wZZ wham it may concern.-

Be it known that I, THOMAS A. EDIsoN, of Llewellyn Park, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Phonogram- .Blanks and Phonograms, '(Oase lid-747,) of

which the following is a specification.

I have found in practice that the most available surface for phonogranrblanks and phonograms is one composed of wax, gum, or other plastic hydrocarbon. Such compounds, however,I find contract and expand under variations of temperature to a much greater extent than paper, wood, metals, andother similar harder substances. While under ordinary conditions the wax or waxlike surface may not be injured by this difi'erence in the coefficient of expansion, yet when subjected to extreme cold the contraction of the wax is so much greater than the harder backing that the wax will crack and destroy the continuity of the surface. For instance, a phonogram-blank or phonogram maybe subjected to a temperature of nearly 100 Fahrenheit at one time and at an other time the temperature may fall below If the waxy substance is sufficiently hard at the high temperature to hold its shape under the pressure of one on the other in a packing-box, it will at the low temperature harden and contract so greatly in excess of the backing ofharder material thatthe wax will crack and render the surface useless.

The object I have in view is to produce a phonogram-blank or phonogram which will have the wax or wax-like surface and will not be subject to the objection that has been stated. This I accomplish by constructing the phonogram-blank or phonogram wholly of the wax or wax-like material. I prefer to mold the entire phonogram-blank of the one wax-like compound; but I may construct the base or backingof the surface of a somewhat diften ent mixture of wax or wax-like materials than that of which the surface is made, so long as the wholehas substantially the same coefficient of expansion.

My phonogram-blank I prefer to mold as a hollow cylinder with a tapering bore for slipping over the tapering phonogram-cylinder of my phonograph.

In the accompanying drawings, forming a part hereof, Figure 1 is an elevation of the phonogram-blank; Fig. 2, a longitudinal section thereof, and Fig. 3 an end View.

A is the cylindrical phonogram blank, molded of the plastic wax or wax-like mate rial, as described, and having a tapering bore.

The invention is also applicable to duplicate phonograms having the phouographic record thereon.

What I claim is- 1. A phonogramblank or phonogram cou structed Wholly of wax or wax-like materials and having the same coefficient of expansion throughout its mass, substantially as set forth.

2. A phonogram-blank or phonogram couslructed as a hollow cylinder wholly of wax or wax-like materials and having the same coefficient of expansion throughoutits mass, substantially as set forth.

3. A phonogram-blank or phonogram constructed as a hollow cylinder, with a tapering bore wholly of wax or waxlike materials, and having the same coefficient of expansion throughout its mass, substantially as set forth.

This specification signed and witnessed this 5th day of December,1887.

THOS. A. nelson.

Witnesses:

WILLIAM PELZER, E. O. ROWLAND. 

